Two new commercial assays for the detection of degradation products of fibrinogen/fibrin (FDP) were evaluated against two standard procedures. The first, a new hemagglutination inhibition (HAI) assay using glutaraldehyde-treated cells, was compared with the tanned red cell hemagglutination inhibition immunoassay (TRCHII). Analysis of 43 samples from patients with a variety of bleeding disorders and thrombotic conditions showed a high degree of correlation between methods (r = 0.934). The second new assay, a rapid slide test using antibody-coated latex particles, was compared with results obtained by electroimmunoassay. There were no significant differences in the results as assessed by two statistical parameters. It was concluded that both new tests are useful for routine use in clinical laboratories.